1. Field of the Invention
This invention relates generally to support devices and more particularly to a support device having a set of pins that may be floated upward to engage an irregular bottom side of an object and then support that object.
2. Prior Art
Devices to engage and then support objects having varying configurations are well known and been in use for many years. Four such devices are described below.
A first support device is disclosed in U.S. Pat. No. 2,985,901. This device is adapted for bonding soles to footwear. The device includes an I-shaped base having a series of aligned, vertically positioned cylinders. In each cylinder is a piston of a T-shaped bar that is pushed upward by a spring in a bottom of the cylinder. Upward movement of the cylinders is restrained by springs on bolts that are secured to respective ends of the bars and extend upward through openings in ends of a top flange of the base. For use, a bottom sole of a shoe is placed on the T-bars. The bars then are forced upward by oil pressure in the cylinders until the shoe sole engages an upper portion of the shoe. Because the sole has an irregular bottom surface, the distance that individual T-bars move depends on the distance between that T-bar and the point of contact with the shoe sole.
A variable contour securing system, as shown in U.S. Pat. No. 4,088,312, is the second support device. This device includes a housing formed by joining a set of blocks. Each block has a bottom space that connect to form a vacuum chamber. A lower end of a vertical bore in each block then connects with the chamber. In each bore is a movable cylinder having a bottom end that seats on a spring in the chamber. On a top end of each cylinder is a suction cup that extends above the housing. Respective passageways in the cylinders link the cups to the vacuum chamber. For use, a vacuum source is activated so that the cups may fasten to a bottom side of an object. Where the object has an irregular shaped bottom side, the respective vertical positions of the cups vary. Once the cups are engaged, the location of the cylinders is secured by air activated locking plugs located in cavities in the housing.
The third device, set out in U.S. Pat. No. 5,152,707, is particularly adapted to support a face panel of a cathode ray tube and includes a box-shaped base. This base is divided into an upper and lower chamber by an intermediate partition. In a top wall of the base and the partition is a set of pairs of vertically aligned openings. Positioned in each opening pair is a sleeve formed with four radially spaced apart, vertical slits. These slits then are covered by a flexible tube fitting about the sleeve. In each sleeve is a pin having a bottom end located in the lower chamber and a top end that extends above the base top wall. For use, the lower chamber is pressurized forcing the pins upward to engage the face panel of a cathode ray tube. Once contact has been made, the base upper chamber is pressurized to force the flexible tubes into the sleeve slots and into contact with the pins. This contact produces a frictional interface that inhibits further pin movement.
The last example is holding apparatus set out in U.S. Pat. No. 5,984,293. This apparatus is particularly adapted to support printed circuit boards and comprises a base formed with a plurality of vertical chambers. In these chambers are respective springs, for example, to upwardly bias bottom foot portions of support pins carried in the chambers. Upper ends of the pins extend through respective aligned openings in a lock plate and a top plate. For use, a board is placed in contact with the pin upper ends so that the pin ends engage a bottom side of the board and electronic components on the board bottom side. The pins are selectively depressed depending on the particular point of engagement. Once the pins are in place, the locking plate is shifted horizontally so that sidewalls of the locking plate openings interact with the pins to secure pin location.
A support device on this invention is particularly adapted to engage an irregularly configured bottom surface of an object and then carry that object. The device includes a support block having a set of upright bores. In each bore is a sleeve for a spring carried in an upper section of an inner opening in the sleeve. A support pin having a bottom end slidably disposed in a lower section of the sleeve inner opening then extends upward through a coil portion of the spring where the pin is held tightly by coils of the spring. Next to the bores in a top wall of the support block is a first guide channel for a movable slide bar. One end of the movable slide bar operatively connects with a reciprocating mechanism attached to one end of the support block.
An uppermost end coil of each spring connects with an upper arm, and the lowermost end coil of the spring connects with a lower arm. The upper arms, for example, are operatively connected to the movable slide bar. The lower arms then are connected to the block or operatively joined to a second slide bar. Where the respective arms joined to the spring end coils vertically align, the second slide bar is located below the first slide bar in the first guide channel. Where the upper and lower arms are arcuately offset, the second arms may be connected to the block or operatively connected to the second slide bar now carried in a second guide channel located in the block top wall on an opposite side of the bores. The slide bars, springs, and sleeves are held in place by a top cover plate attached to the top wall of the support block. This cover plate includes a set of openings for top ends of pins.
The bottom ends of the pins fit one each over one end of a set of transversely positioned conduits formed in a top surface of a bottom cover plate fastened to a bottom wall of the support block. Opposite ends of these conduits intersect with an air distribution channel in the support block bottom wall. An open end of this channel then connects with a transversely positioned air supply duct in an opposite end of the support block.
For use, the device supply duct is connected to an air supply. Air flowing from the duct to the distribution channel is regulated by a valve carried by the support block and located to extend into the distribution channel open end. To allow the pins to float upwardly, the reciprocating mechanism is activated to move the arms and thereby rotate the coils of the springs. Where, for example, the coils of the springs are wound clockwise from the uppermost end coil to the lowermost end coil, a clockwise rotational movement of the uppermost end coils transfers to the remainder of the coils to effect a diameter increase of each spring coil portion. Counterclockwise movement of the spring lowermost end coils produces a like effect. Were the springs wound counterclockwise, the direction of the spring upper and lowermost end coil rotation is reversed to produce a like effect. The arms connected to the spring end coils facilitate the transfer of force needed to effect coil rotation and the resulting coil enlargement. As the spring coils are enlarged, the springs shift from a locking mode to a release mode. Once the springs are in a release mode, the pins float upward from air flowing through the conduits and under the pin bottom ends. Respective upward movement of the pins terminates when the top end of a pin contacts a particular point on the bottom surface of the object thereabove. The reciprocating mechanism then is deactivated so that the arms return to the arcuate spacing that places the spring coil portions in their locking mode so that the pins support the object.
The support device with floating pins of the invention provides several advantages over like devices known or in use.
A first advantage is that pin support can be readily tailored to support objects having varying bottom surface configurations. Where, for example, this inventive device is used to support a printed circuit board during connection of various electronic components attached on a bottom surface of the board, the pins engage the board surface, electronic components attached to the board, and component connections. Because the flow of air that floats the pins upward is slight, there is no damage to or dislocation of an electronic component if a pin engages a component. Additionally, there is no component dislocation when the pins are locked in place.
A second advantage is that the pattern of pin support can be readily customized to support a second object having a different bottom surface configuration. By disconnecting the air supply to the pins and unlocking the pins, the pins retract under the force of gravity. Support of the second object may be effected simply by reconnecting the air supply to float the pins upward until the pins engage the second object bottom surface. The pins then are locked in place by allowing the springs to return to their locking mode. Note that because the pins may be readily withdrawn and then reset, objects may be slide over and away this support device. There is no need for an object to be lifted on to or off the device.
A further advantage is that top ends of the pins may be shaped to engage the object bottom surface in a precise complementary manner. Where the irregularity of the object bottom surface is pronounced, it may be advantageous for a top end of a pin to be pointed to engage only a small area of this surface. Additionally, once the pins of this device are locked in place, these pins may carry heavy loads. Thus, with adequate support from below, substantial workloads may be applied to a top surface of the object.
A next advantage is that a series of devices may be joined to form an apparatus having varying matrices of supporting pins. Apparatus formation is facilitated by extending aligning rods transversely through openings in the support blocks of the devices and then connecting an outlet port of one device supply duct to an inlet port of the supply duct of an adjacent device. Note that where the apparatus comprises more than one support device of this invention, only one reciprocating device is needed to lock and unlock the springs.
Lastly, the support device of this invention has an extended useful life. Models of the device have been cycled more a one million times without a failure. Since the device has application in continuous, high production manufacturing, device failure must be infrequent.